1. Placental transmission. III. The amino acids, non-protein nitrogen, urea, and uric acid in fetal and maternal whole blood, plasma and corpuscles;Plass;Bull. Hopkins Hosp.,1925
2. Observations on the equilibrium of urea between mother and fetus;McGaughey;Am. J. Obstet. Gynecol.,1959
3. Ammonia nitrogen, urea, and uric acid blood levels in the mother and in both umbilical vessels at delivery;Rubaltelli;Biol. Neonate,1968
4. Urea production in the mammalian fetus and its metabolic implications;Gresham,1971
5. Clearance of inert molecules, Na and Cl ions across the primate placenta;Battaglia;Am. J. Obstet. Gynecol.,1968